Arsenic-induced genotoxicity in Nile tilapia (Orechromis niloticus); the role of Spirulina platensis extract

Assessment of ecological status of Uppanar and Vellar estuaries through multivariate pollution indices

Multivariate pollution degree indices were utilized to evaluate the environmental condition of the Uppanar and Vellar estuaries. The Trophic Index (TRIX) indicates a state of "moderate eutrophication" with a value of 4.92, while the Trophic State Index (TSI) ranged from 40.3 to 57.2, categorizing the trophic states from "oligotrophic" to "eutrophic". The Comprehensive Pollution Index (CPI) showed a range of 0.13 to 0.94, classifying pollution levels from "unpolluted" to "slightly polluted". The study revealed that the Uppanar and Vellar estuaries underwent seasonal variations, transitioning from an oligotrophic state during the post-monsoon and summer periods to a eutrophic state in the pre-monsoon and monsoon seasons. The application of multivariate statistical tools allowed the identification of pollution indicator species to assess the estuarine systems. The insights gained from this study can be valuable for assessing other ecosystems facing similar anthropogenic activities, providing a basis for informed management and conservation strategies.

The effects of dietary Spirulina platensis or curcumin nanoparticles on performance, body chemical composition, blood biochemical, digestive enzyme, antioxidant and immune activities of Oreochromis niloticus fingerlings

CONTEXT

Recently, prioritize has been given to using natural phytogenic or nano compounds as growth promoters and immunostimulants in fish diets as an alternative to antibiotics.

AIMS

The main propose of this trial was to determine the impact of supplementing diets with spirulina or curcumin nanoparticles on the performance and health indicators of Nile tilapia fingerlings.

METHODS

In a 56-day feeding trial, 180 tilapia fingerlings were assigned into three main groups, as follows: 1st, control group, 2nd, Spirulina platensis (SP; 5 g kg-1 diet) and 3rd, curcumin nanoparticles (CUR-NPs; 30 mg kg-1 diet).

KEY RESULTS

Incorporating tilapia diets with SP or CUR-NPs significantly improved performance, body chemical analysis, blood biochemical and hematological indices, digestive enzyme activities, and antioxidant and immunostimulant features compared to the control.

CONCLUSION

Fortified tilapia diets with CUR-NPs or SP efficiently boost the productivity and health of Nile tilapia fingerlings.

IMPLICATIONS

The research introduces new practical solutions for applying safe feed additives as alternatives to antibiotics in tilapia farming.

Exposure to pyrogallol impacts the hemato-biochemical endpoints in catfish (Clarias gariepinus)

Pyrogallol is widely used in several industrial applications and can subsequently contaminate aquatic ecosystems. Here, we report for the first time the presence of pyrogallol in wastewater in Egypt. Currently, there is a complete lack of toxicity and carcinogenicity data for pyrogallol exposure in fish. To address this gap, both acute and sub-acute toxicity experiments were conducted to determine the toxicity of pyrogallol in catfish (Clarias gariepinus). Behavioral and morphological endpoints were evaluated, in addition to blood hematological endpoints, biochemical indices, electrolyte balance, and the erythron profile (poikilocytosis and nuclear abnormalities). In the acute toxicity assay, it was determined that the 96 h median-lethal concentration (96 h-LC50) of pyrogallol for catfish was 40 mg/L. In sub-acute toxicity experiment, fish divided into four groups; Group 1 was the control group. Group 2 was exposed to 1 mg/L of pyrogallol, Group 3 was exposed to 5 mg/L of pyrogallol, and Group 4 was exposed to 10 mg/L of pyrogallol. Fish showed morphological changes such as erosion of the dorsal and caudal fins, skin ulcers, and discoloration following exposure to pyrogallol for 96 h. Exposure to 1, 5, or 10 mg/L pyrogallol caused a significant decrease in hematological indices, including red blood cells (RBCs), hemoglobin, hematocrit, white blood cells (WBC), thrombocytes, and large and small lymphocytes in a dose-dependent manner. Several biochemical parameters (creatinine, uric acid, liver enzymes, lactate dehydrogenase, and glucose) were altered in a concentration dependent manner with short term exposures to pyrogallol. Pyrogallol exposure also caused a significant concentration-dependent rise in the percentage of poikilocytosis and nuclear abnormalities of RBCs in catfish. In conclusion, our data suggest that pyrogallol should be considered further in environmental risk assessments of aquatic species.

Bioaccumulation and Bioremediation of Heavy Metals in Fishes-A Review

Heavy metals, the most potent contaminants of the environment, are discharged into the aquatic ecosystems through the effluents of several industries, resulting in serious aquatic pollution. This type of severe heavy metal contamination in aquaculture systems has attracted great attention throughout the world. These toxic heavy metals are transmitted into the food chain through their bioaccumulation in different tissues of aquatic species and have aroused serious public health concerns. Heavy metal toxicity negatively affects the growth, reproduction, and physiology of fish, which is threatening the sustainable development of the aquaculture sector. Recently, several techniques, such as adsorption, physio-biochemical, molecular, and phytoremediation mechanisms have been successfully applied to reduce the toxicants in the environment. Microorganisms, especially several bacterial species, play a key role in this bioremediation process. In this context, the present review summarizes the bioaccumulation of different heavy metals into fishes, their toxic effects, and possible bioremediation techniques to protect the fishes from heavy metal contamination. Additionally, this paper discusses existing strategies to bioremediate heavy metals from aquatic ecosystems and the scope of genetic and molecular approaches for the effective bioremediation of heavy metals.

Chronic intake of an enriched diet with spirulina (Arthrospira maxima) alleviates the embryotoxic effects produced by realistic concentrations of tetracycline in Danio rerio

Tetracycline (TC) is one of the most consumed antibiotics worldwide. Due to its high consumption, recent studies have reported its presence in aquatic environments and have assessed its effects on fish, algae, and daphniids. However, in most of those works, authors have tested TC toxicity at concentrations higher than the ones reported in the water matrix. Herein, we aimed to assess the likely embryotoxic and oxidative damage induced by environmentally relevant concentrations of TC in embryos of Danio rerio. Moreover, we seek to determine whether or not an enriched diet with spirulina can alleviate the embryotoxic damage produced by TC. Our findings indicated that TC at concentrations of 50 to 500 ng/L induced pericardial edema, tail deformities, and absence of head and fin in embryos after 96 h of exposure. Moreover, this antibiotic prompted the death of embryos in a concentration-dependent manner. According to our integrated biomarker response index, TC induced oxidative damage on Danio rerio embryos, as star plots showed a tendency to lipoperoxidation, hydroperoxides, and protein carbonyl content. Spirulina reduced the toxicity of TC by diminishing the levels of oxidative damage biomarkers, which resulted in a decrease in the rate of death and malformed embryos. Overall, TC at concentrations of ng/L prompted oxidative stress and embryotoxicity in the early life stages of Danio rerio; nonetheless, the algae spirulina was able to reduce the severity of those effects.

Reproductive Toxicity and Recovery Associated With 4-Non-ylphenol Exposure in Juvenile African Catfish (Clarias garepinus)

Although, the effects of 4-non-ylphenol (4-NP) on fish's reproductive hormones were assessed in several studies using adult models, however, the effect of this endocrine disruptor on immature fish's reproductive hormones was not addressed commonly. We aimed to study the apoptosis induction, hematotoxicity, reproductive toxicity, and the recovery associated with 4-NP exposure in juvenile African catfish [Clarias garepinus) using some hormones [17β-estradiol (E2), testosterone (T), follicle-stimulating hormone (FSH), and luteinizing hormone (LH)] and gonad histology as biomarkers. The toxic effects of 4-NP have been studied in many animal models, but there is still limited knowledge about the dose-dependent damage caused by 4-NP exposure in juvenile Clarias gariepinus. A healthy juvenile C. gariepinus was categorized into four groups (n = 3/group; three replicates in each group). The first group was the control, and the other three groups were subjected to 4-NP concentrations as 0.1, 0.2, and 0.3 mg/L for 15 days; they were left for a recovery period of another 15 days. The reproductive hormones of C. gariepinus exposed to 4-NP for 15 days exhibited significant variations between the treatment groups and the control (P < 0.05), which were evident in E2 and T-values, whereas FSH, LH, total protein, and lipid peroxidation values showed non-significant differences among all groups at P < 0.05. Such a situation referred to the fact that the 15-day recovery period was insufficient to remove the impacts of 4-NP doses in concern. The trend of dose-dependent increase/decrease was recorded for T, E2, FSH, and LH. The histopathological alterations of 4-NP treated in gonad tissues were recorded in juvenile C. gariepinus, reflecting their sensitivity to 4-NP estrogenic-like effects. Overall, our results investigate that recovery has improved the reproductive toxicity caused by 4-NP in juvenile C. garepinus. Significant variations between the treated groups and the control group (P < 0.05) were evident in hematological parameters except for hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). The parameters exhibiting significance decreased with such increased doses [red blood cells (RBCs), hematocrit (Hct), and white blood cells (WBCs)]. Similar patterns of significant variations toward the increase or decrease were recorded following the 15-day recovery period. Apoptotic frequency in erythrocytes and brain cells has increased significantly with increased 4-NP exposure, indicating that 4-NP caused cytotoxic effects, such as apoptosis in a dose-dependent manner. However, these cellular alterations greatly decreased after the 15-day recovery period.

Microplastics-Induced Eryptosis and Poikilocytosis in Early-Juvenile Nile Tilapia (Oreochromis niloticus)

This study aims to assess the impact of microplastics (MPs) on erythrocytes using eryptosis (apoptosis) and an erythron profile (poikilocytosis and nuclear abnormalities), considered to be novel biomarkers in Nile tilapia (Oreochromis niloticus). In this study, four groups of fish were used: The first was the control group. In the second group, 1 mg/L of MPs was introduced to the samples. The third group was exposed to 10 mg/L of MPs. Finally, the fourth group was exposed to 100 mg/L of MPs for 15 days, following 15 days of recovery. The fish treated with MPs experienced an immense rise in the eryptosis percentage, poikilocytosis, and nuclear abnormalities of red blood cells (RBCs) compared with the control group in a concentration-dependent manner. Poikilocytosis of MP-exposed groups included sickle cell shape, schistocyte, elliptocyte, acanthocyte, and other shapes. Nuclear abnormalities of the MPs-exposed groups included micronuclei, binucleated erythrocytes, notched, lobed, blebbed, and hemolyzed nuclei. After the recovery period, a greater percentage of eryptosis, poikilocytotic cells, and nuclear abnormalities in RBCs were still evident in the groups exposed to MPs when crosschecked with the control group. The results show concerning facts regarding the toxicity of MPs in tilapia.

Investigating the effects of copper sulfate and copper oxide nanoparticles in Nile tilapia (Oreochromis niloticus) using multiple biomarkers: the prophylactic role of Spirulina

Copper has toxic effects in fish, whereas the cyanobacterium Spirulina reportedly has protective effects against metal toxicity in various animal species. The current study, therefore, aimed to investigate the prophylactic role of Spirulina platensis against the effects of copper sulfate (CuSO4) and copper oxide nanoparticles (CuO-NPs) in Nile tilapia (Oreochromis niloticus). Biochemical, antioxidant, erthyron profile and histopathological endpoints were assessed after for 15 days of exposure in five separate treatment groups: (1) fish pre-fed the normal diet (control), (2) fish pre-fed the normal diet and exposed to 15 mg/L of CuSO4, (3) fish pre-fed the normal diet augmented with 0.25% Spirulina and exposed to 15 mg/L of CuSO4, (4) fish pre-fed the normal diet and exposed to 15 mg/L of CuO-NPs, and (5) fish pre-fed the normal diet augmented with 0.25% Spirulina and exposed to 15 mg/L CuO-NPs. Exposure to CuSO4 or CuO-NPs significantly increased superoxide dismutase and catalase activities in fish, as well as serum total protein, glucose, aspartate aminotransferase, alanine aminotransferase, creatinine, and uric acid concentrations. In contrast, most hematological indices in fish significantly decreased after CuSO4 or CuO-NPs exposure. Moreover, CuSO4 and CuO-NPs caused a significant increase in the percentage of poikilocytosis and nuclear abnormalities of red blood cells, as well as histopathological changes in the brain, liver, intestine, and kidneys. Importantly, Spirulina supplementation mitigated against physiological disruption caused by CuSO4 or CuO-NPs.

Ameliorating effects of dietary Haematococcus pluvialis on arsenic-induced oxidative stress in rainbow trout (Oncorhynchus mykiss) fillet

The current study was performed to investigate the protective effects of dietary Haematococcus pluvialis (H. pluvialis) on the oxidative stress induced by arsenic in rainbow trout (Oncorhynchus mykiss). The fish (20.70 ± 0.09 g) were fed with H. pluvialis at the levels of 0.28, 0.56, and 1.12 g 100 g^-1 diet for 60 days. Then, each group was divided into two subgroups. In one of the subgroups, fish were exposed to arsenic challenge at a level of 9.1 mg/L. The other subset was used as the negative control. After the 96 h of toxicity test, protein and lipid oxidative levels, antioxidant-relevant gene expression as well as several chemical factors, including pH and peroxide value and moisture content, were evaluated in the fillet samples. Results showed that feeding with H. pluvialis decreased the levels of pH, peroxide value, as well as protein and lipid oxidation levels in treatment groups. Besides, the expression of antioxidant genes was significantly increased in the groups administrated with H. pluvialis. Based on the results of this study, feeding H. pluvialis attenuated the oxidative stress induced by arsenic in rainbow trout fillet through improving the antioxidant defense system.

Spirulina platensis Alleviated the Oxidative Damage in the Gills, Liver, and Kidney Organs of Nile Tilapia Intoxicated with Sodium Sulphate

Simple Summary

Nile tilapia (Oreochromis niloticus) are expected to suffer from oxidative stress induced by sodium sulphate in the ecosystem. Herein, we proposed that dietary Spirulina platensis could relieve the impacts of sodium sulphate on tilapia. The hepatic antioxidative and related activities were decreased under sodium sulphate exposure. However, dietary S. platensis alleviated the tissue antioxidative overexpression compared to the sodium sulphate and control groups. This study implies that natural dietary antioxidants can be applied in aquatic organisms to alleviate the features induced by toxicants and xenobiotics.

Abstract

The current study aimed at assessing the recuperative roles of dietary Spirulina platensis on the antioxidation capacity of Nile tilapia (Oreochromis niloticus) exposed to sodium sulphate for eight weeks. In brief, fish were allocated into four groups with three triplicates per group, where a group fed on a commercial basal diet served as control, a group was intoxicated with sodium sulphate (SS) 5.8 mg/L, another group was fed a diet supplemented with 1% S. platensis (SP), and the last group was fed 1% SP and concomitantly intoxicated with 5.8 mg/L sodium sulphate (SP/SS). Tissue antioxidative indices of each fish were measured as follows: glutathione peroxidase (GSH-Px) activity in muscles, catalase (CAT) and superoxide dismutase (SOD) activities in gills, and total antioxidant capacity (T-AOC) in the liver and kidney. Moreover, the expression of hepatic SOD, GSH-Px, and glutathione-S-transferase (GST) genes was also determined. It was found that tissue CAT, SOD, and GSH-Px activities as well as the T-AOC levels were significantly decreased in the SS group (p < 0.05). Moreover, there was a significant downregulation of hepatic SOD, GSH-Px, and GST genes in SS-exposed fish (p < 0.05). Interestingly, simultaneous dietary supplementation with SP provided a marked attenuation of the tissue antioxidative parameters when compared with the SS and control groups. To conclude, the present study exemplifies that dietary SP supplementation could be a beneficial abrogation of SS-induced tissue oxidative stress in the exposed fish.

Hepato-nephrotoxicity in late juvenile of Oreochromis niloticus exposed to gibberellic acid: Ameliorative effect of Spirulina platensis

The current work intended to inspect the hepato-nephrotoxicity of gibberellic acid (GA₃) in juvenile of Oreochromis niloticus as well as the possibility of restoration after dietary addition of different concentrations of Spirulina platensis (SP). Fishes were evenly assorted into five groups: Group I assigned as control, Group II fed on basal diet and exposed to 150 mg/L gibberellic acid (GA₃). The 3rd, 4th, and 5th groups exposed to150 mg/L gibberellic acid (GA₃) and previously fed for two months on SP supplemented diets at levels of 5, 20, and 100 g/kg, respectively. Fish serum were utilized to check glucose, total protein, hepatic and renal functions, enzymatic and non-enzymatic antioxidants activities (superoxide dismautase; SOD, catalase; CAT, and total antioxidant capacity; TAC) as well as histopathological alterations in liver and kidney. The results showed that creatinine, uric acid, liver enzymes, glucose, total protein, SOD, and CAT were significantly elevated in GA3-treated group. Liver of GA3-treated fish manifested some histopathological changes (hypertrophy, cytoplasmic vacuolization, and apoptotic cells with pyknotic nuclei, necrosis, dilated blood sinusoids, and lymphocytic aggregation around the central veins). Kidney of GA3-exposed fish revealed edema of the epithelium lining of some renal tubules and some showed vacuolar degeneration and dissociation. Hypertrophy in the glomerulus was observed with dilated blood capillaries. SP supplementation restored these biochemical, antioxidants, and histological changes near to control levels. This improvement was higher with 100 g/kg SP showing concentration dependency. According to this study we can conclude that SP supplementation can improve the hepato- and nephrotoxicity caused by GA₃ exposure indicating its role as potent antioxidant food additive.

Cytotoxic and genotoxic effects of arsenic on erythrocytes of Oryzias latipes: Bioremediation using Spirulina platensis

BACKGROUND

Exposure to the environmental pollutants poses a serious threat to aquatic organism. The arsenic exposure in fish increases the risk of developing serious alterations from embryo to adult.

OBJECTIVES

The present investigation was done to study the toxic effects of heavy metal arsenic [As(III)] on medaka (Oryzias latipes). Morphological alterations, apoptosis, nuclear abnormalities, and genotoxic biomarkers in erythrocytes were used to determine the stress caused by arsenic (As) exposure.

METHODS

Medaka was exposed to As for 15 days at two toxic sublethal concentrations (7 ppm and 10 ppm) in combination with Spirulina platensis (SP) treatment as antioxidant algae at 200 mg/L.

RESULTS

Results were consistent with a previous study results on tilapia. Exposure of medaka to As resulted in a dose-dependent increase in most the biomarkers used in the current study. Fish exposed to10 ppm As showed highest level of DNA damage. For the first time to our knowledge, using SP to counter the As toxicity in medaka, DNA damage restored to control levels.

CONCLUSION

Accordingly, those results suggests that SP can protect medaka in aquaculture against As-induced damage by its ability as reactive oxygen species (ROS) reducer, antioxidant role, and DNA damage scavenger.

Ameliorative effect of Spirulina platensis against lead nitrate-induced cytotoxicity and genotoxicity in catfish Clarias gariepinus

The present study was designed to investigate the protective role of dietary supplementation of Spirulina platensis (SP) against cytotoxic and genotoxic effects of lead nitrate in Clarias gariepinus. Four groups of fishes were used: first group as control which fed on basal diet, second group fed on basal diet and exposed to (1 mg/L of lead nitrate), third group fed on diet containing 0.25% SP and exposed to (1 mg/L of lead nitrate), and fourth group fed on diet containing 0.5%SP and exposed to (1 mg/L of lead nitrate). Fish samples were taken at 2nd and 4th week of exposure. The hematological indices of lead nitrate-exposed group were decreased significantly compared to the control group at 2nd and 4th week of exposure. Lead nitrate caused a significant increase in the percentage of poikilocytosis, micronuclei, and apoptotic cells as well as comet tail length and olive tail moment compared with the control group at 2nd and 4th week of exposure. The highest level of damage was found on 4th week of exposure with all parameters. Dietary inclusion of SP ameliorated these cytotoxic and genetic changes, as well as this amelioration was concentration and time dependent. Consequently, the present study proposed that the addition of SP to the fish diet can be used as a promising protective agent to oppose cytotoxic and genotoxic effects of lead nitrate in aquaculture. Graphical abstract.

Protective role of Spirulina platensis against UVA-induced haemato-biochemical and cellular alterations in Clarias gariepinus

Recently, it has become widely recognized that ultraviolet A (UVA) exposure is harmful for both aquatic and terrestrial organisms. Many studies have reported the effects of UVA on aquatic animals, especially fish, but little is known about the antioxidant role of microalgae in ameliorating the negative effects of UVA exposure. Recently, there has been great interest in using Spirulina platensis (SP) as a dietary antioxidant agent. Therefore, this study aimed to investigate the protective role of SP against UVA-induced effects by analysing haemato-biochemical alterations and erythrocyte cytotoxic and genotoxic biomarkers in African catfish (Clarias gariepinus). Fish were exposed to UVA, UVA + 100 mg/L SP extract, UVA + 200 mg/L SP extract for 3 days (UVA exposure: 1 h/day), and were not subjected to treatment (control group). The results showed the presence of some morphological malformations in red blood cells (RBCs) after UVA exposure. Additionally, nuclear abnormalities, including micronuclei, were observed. UVA induced alterations in most of the haemato-biochemical indices. Adding SP to the fish aquaria restored the haemato-biochemical parameters to their control values. In addition, SP repaired cellular damage in a dose-dependent manner. We conclude that SP plays a modulatory role in preventing and/or repairing the haemotoxic effects induced by UVA.

Selenium-Containing Protein From Selenium-Enriched Spirulina platensis Attenuates Cisplatin-Induced Apoptosis in MC3T3-E1 Mouse Preosteoblast by Inhibiting Mitochondrial Dysfunction and ROS-Mediated Oxidative Damage

Accumulated evidences have verified that cancer chemotherapy may increase the risk of osteoporosis and severely affected the life quality. Osteoclasts hyperactivation was commonly accepted as the major pathogenesis of osteoporosis. However, the role of osteoblasts dysfunction in osteoporosis was little investigated. Our previous study has confirmed that selenium-containing protein from selenium-enriched Spirulina platensis (Se-SP) exhibited enhanced hepatoprotective potential through inhibiting oxidative damage. Herein, the protective effect of Se-SP against cisplatin-induced osteoblasts dysfunction in MC3T3-E1 mouse preosteoblast was investigated, and the underlying mechanism was evaluated. The results indicated that cisplatin dramatically decreased cell viability of preosteoblast by triggering mitochondria-mediated apoptosis pathway. Cisplatin treatment also caused mitochondrial dysfunction and reactive oxide species (ROS)-mediated oxidative damage. However, Se-SP pre-treatment effectively prevented MC3T3-E1 cells from cisplatin-induced mitochondrial dysfunction by balancing Bcl-2 family expression and regulating the opening of mitochondrial permeability transition pore (MPTP), attenuated cisplatin-induced oxidative damage through inhibiting the overproduction of ROS and superoxide anion, and eventually reversed cisplating-induced early and late apoptosis by inhibiting PARP cleavage and caspases activation. Our findings validated that Se-SP as a promising Se species could be a highly effective way in the chemoprevention and chemotherapy of oxidative damage-mediated bone diseases.

The protective role of Spirulina platensis to alleviate the Sodium dodecyl sulfate toxic effects in the catfish Clarias gariepinus (Burchell, 1822)

Sodium dodecyl sulfate (SDS) as anionic surfactant is common in household and personal care products and reach in the aquatic ecosystems from different applications. Present work aimed to study the effects of SDS and the potential ameliorative influence of Spirulina platensis (SP) in the African catfish Clarias gariepinus. Fish was exposed to SDS and SP, individually or in combination in four equal groups for two weeks. The 1st group (control), 2nd group (SDS-treated), 3rd group (SDS, 0.1 mg L^-1 + SP, 100 mg L^-1 water) and 4th group (SDS, 0.1 mg L^-1 + SP, 200 mg L^-1). Serum samples were used to analyze hepatic and renal functions, electrolytes, genetic, and antioxidant biomarkers. The results revealed that SDS exposure induced hepatic and renal dysfunction, electrolytes imbalance, as well as significant disruption in enzymatic and non-enzymatic antioxidants, and increase in alterations, micronuclei and apoptosis percentages in erythrocytes. SP addition restored these biochemical and genetic variations close to control levels. Thus, the present study suggests that SP could protect the catfish against SDS-induced injury by scavenging ROS, sustaining the antioxidant status and diminishing DNA oxidative damage.

Sensitivity of medaka (Oryzias latipes) to 4-nonylphenol subacute exposure; erythrocyte alterations and apoptosis

The present study was undertaken to assess the effects of the endocrine-disrupting compound; 4-nonylphenol (4-NP) in medaka (Oryzias latipes). The frequencies of erythrocyte alterations, apoptosis, and micronuclei were used as biological indicators of damage. Medaka were exposed 15 days to 4-NP at three sublethal concentrations (50, 80, and 100 μg/l 4-NP) and results compared with those of a previous study using catfish as an animal model. Exposure of medaka resulted in a dose-dependent increase in the frequency of erythrocyte alterations, apoptosis and micronucleus (MN). Many morphological alterations and nuclear abnormalities were observed, including acanthocytes, lobed nucleus, eccentric nucleus, fragmented nucleus, blebbed nucleus, binuclei, deformed nucleus, notched nucleus, hemolysed cells, crenated cells, teardrop-like cells, and schistocytes. Mortality was recorded after treatment with 80 and 100 μg/l 4-NP, indicating that medaka are more sensitive than catfish to 4-NP exposure. We concluded that, 4-NP causes several malformations in the shape and number of erythrocytes in medaka, indicating its genotoxicity.

Hepatoprotective efficacy of Spirulina platensis against lead-induced oxidative stress and genotoxicity in catfish; Clarias gariepinus

Lead (Pb) is a toxic environmental pollutant that induces a broad range of biochemical and physiological hazards in living organisms. We investigated the possible hepatoprotective effects of Spirulina platensis (SP) in counteracting the Pb-induced oxidative damage. Ninety-six adult African catfish were allocated into four equal groups. The 1st group (control) fed basal diet while the 2nd group (Pb-treated) fed on basal diet and exposed to 1mg Pb(NO₃)₂/L. The 3rd and 4th groups fed SP-supplemented basal diets at levels of 0.25% and 0.5%, respectively and exposed to Pb. Serum samples were used to analyze hepatic function biomarkers, electrolytes, and oxidant and antioxidant status. Lipid peroxidation and DNA fragmentation were determined in the liver tissues. Pb exposure induced hepatic dysfunction, electrolytes (Na⁺, K⁺, Ca⁺², and Cl^-) imbalance, as well a significant decrease in GSH content, and LDH, AChE, SOD, CAT and GST enzymes activity. SP supplementation reverted these biochemical and genetic alterations close to control levels. This amelioration was higher with 0.5% SP and at the 4th week of exposure, showing concentration- and time-dependency. Thus, the current study suggests that SP could protect the catfish liver against lead-induced injury by scavenging ROS, sustaining the antioxidant status and diminishing DNA oxidative damage. The dietary inclusion of SP can be used as a promising protective agent to counteract oxidative stress-mediated diseases and toxicities.

Protective Effect of Azadirachta indica and Vitamin E Against Arsenic Acid-Induced Genotoxicity and Apoptosis in Rats

Sodium arsenite (NaAsO₂) is one of the major environmental toxicants with severe toxicological consequences in some developing and developed countries. Rats in Group A received normal saline. Genotoxicity and apoptosis were induced by single intraperitoneal injection of 10 mg/kg sodium arsenite to rats in Groups B-F. Rats in Groups C and D had earlier been pretreated with Azadirachta indica (100 and 200 mg/kg) or E and F with vitamin E (50 and 100 mg/kg), respectively. Markers of oxidative stress, inflammation, hepatic damage, genotoxicity, and apoptosis were assessed. Pretreatment of rats with either Azadirachta indica or vitamin E led to a significant (p <.05) increase in the activities of glutathione-S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), and reduced glutathione (GSH) in the liver compared to the group that received NaAsO₂ alone. Markers of oxidative stress and inflammation, malondialdehyde (MDA), hydrogen peroxide (H₂O₂) generation, nitric oxide (NO), and myeloperoxidase (MPO), were significantly (p <.05) lowered in rats pretreated with Azadirachta indica or vitamin E. The frequency of micronucleated polychromatic erythrocytes (MNPCEs) and expression of caspase-3 were significantly (p <.05) reduced in rats pretreated with either Azadirachta indica or vitamin E compared to rats intoxicated with arsenite. Histopathology of the liver showed areas of infiltration of inflammatory cells with deaths of numerous hepatocytes in NaAsO₂-intoxicated rats, and these were reversed by Azadirachta indica. Together, we report for the first time the genoprotective and antiapoptotic effect of Azadirachta indica by a significant reduction in the frequency of micronuclei-induced apoptosis and oxidative stress by arsenic intoxication.